RITM and JAPOHR project successfully introduce the laboratory standard virus to the Philippines

Recently, it has been a problem in the Philippines that no facility can perform rabies gold standard test (RFFIT and FAVN tests adapted by WHO and OIE) test to measure antibody (Immunity after vaccination) in human and animals. Rabies is a fatal but vaccine-preventable disease. The antibody test is indispensable to know whether humans and animals have adequate immunities against Rabies virus. The information of the antibody level (immunity level) for rabies is important for rabies-related health workers and to determine the vaccination coverage rate in dogs, and to certificate animals exported to other countries.

The challenge virus standard strain CVS-11 (the laboratory standard strain) is required for the tests. Therefore, the Research Institute for Tropical Medicine (RITM), The Philippines, and our JAPOHR project collaborated to import the strain from a world professional institution with the permission of DA-BAI.

Then, in July 2019, Prof. Nishizono   (JAPOHR project leader) and Dr. Yamada,   Department of Microbiology, Faculty of   Medicine, Oita University, visited RITM.  Their the laboratory is the sole medical laboratory researching rabies in Japan and has lots of experience of the laboratory procedures of the laboratory strain.

Ms. Lindsay Fajardo and Dr. Criselda Bautista
doing culture  while
Dr. Yamada observes on their technique.

  To conduct the virus neutralizing antibody test in RITM, it was necessary to culture and amplify the freeze-dried virus in cell lines at first. However, the first trial using  BHK-21 cells according to the protocol from  OIE was failed.

It is well known that RABV is a neurotropic virus, NA-C1300 is more preferable than the cell line BHK-21. Therefore, Dr. Yamada brought NA-C1300 cells to the Special Pathogens Laboratory (SPL) of RITM from Japan just in case. NA-C1300 cells are used to amplify the rabies virus in the Oita laboratory.

                                                                

The smile of success. Dr Yamada with Ms Leilanie Nacion, Ms. Lindsay Fajardo and Ms. Joanna Sorino smiling while showing rabies positive NA-C1300 cells. 

 

Rabies virus (CVS-11)
infected NA-C1300 cells. 

    Then, Prof. Nishizono and Dr. Yamada gave technical advice for the special laboratory procedures using NA-C1300 cells to the SPL staff.

After incubation for a week,

Finally, we did it!!!

The increasing the laboratory rabies virus was confirmed. And the immunochromatographic test (ICT) that was developed by Prof. Nishizono was used for the confirmation. Of note, the ICT was able to detect the viral antigen in the culture supernatant within 15 min without special equipment.

Before leaving the RITM, both Dr. Nishizono and Dr. Yamada also gave advice and did technical transfer to the SPL staff how to check the virus strain increased to prepare the virus stock used for the antibody tests.

RFFIT (Rapid Fluorescent Focus Inhibition Test) can measure the titer of rabies neutralizing antibodies present in the blood within 30 hours. We believe that RITM will introduce the test in close cooperation with JAPOHR team members soon. Implementation of “gold standard” virus neutralization test (RFFIT) into RITM will strengthen laboratory capacity for rabies diagnosis and make it the only institution capable of performing it in the Philippines and facilitate the rabies control activities. 

We would like to thank and congratulate members of RITM (Ms. Nacion and Sorino, and Dr. Bautista) and JAPOHR (Prof. Nishizono, Drs Yamada and Kimitsuki, and Ms. Fajardo) teams on very good and promising preliminary results. We would also like to wish them the best of luck in the remainder of their experimental processes until they reach our goal.